ChatMessageValidator: Additional validation.

lib/pleroma/web/activity_pub/object_validators/chat_message_validator.ex

@@ -93,12 +93,14 @@ def validate_content_or_attachment(cng) do
   - If both users are in our system
   - If at least one of the users in this ChatMessage is a local user
   - If the recipient is not blocking the actor
+  - If the recipient is explicitly not accepting chat messages
   """
   def validate_local_concern(cng) do
     with actor_ap <- get_field(cng, :actor),
          {_, %User{} = actor} <- {:find_actor, User.get_cached_by_ap_id(actor_ap)},
          {_, %User{} = recipient} <-
            {:find_recipient, User.get_cached_by_ap_id(get_field(cng, :to) |> hd())},
+         {_, false} <- {:not_accepting_chats?, recipient.accepts_chat_messages == false},
          {_, false} <- {:blocking_actor?, User.blocks?(recipient, actor)},
          {_, true} <- {:local?, Enum.any?([actor, recipient], & &1.local)} do
       cng
@@ -107,6 +109,10 @@ def validate_local_concern(cng) do
         cng
         |> add_error(:actor, "actor is blocked by recipient")
 
+      {:not_accepting_chats?, true} ->
+        cng
+        |> add_error(:to, "recipient does not accept chat messages")
+
       {:local?, false} ->
         cng
         |> add_error(:actor, "actor and recipient are both remote")

test/web/activity_pub/object_validator_test.exs

@@ -223,6 +223,17 @@ test "does not validate if the recipient is blocking the actor", %{
       refute match?({:ok, _object, _meta}, ObjectValidator.validate(valid_chat_message, []))
     end
 
+    test "does not validate if the recipient is not accepting chat messages", %{
+      valid_chat_message: valid_chat_message,
+      recipient: recipient
+    } do
+      recipient
+      |> Ecto.Changeset.change(%{accepts_chat_messages: false})
+      |> Pleroma.Repo.update!()
+
+      refute match?({:ok, _object, _meta}, ObjectValidator.validate(valid_chat_message, []))
+    end
+
     test "does not validate if the actor or the recipient is not in our system", %{
       valid_chat_message: valid_chat_message
     } do